Tainted Air

Just two hours of breathing in concentrated Toronto air can raise your blood pressure and constrict your arteries. The air we usually breathe is unlikely to harm healthy people, but if you already have heart or lung troubles, inhaling the high levels of small particles in the city’s air could be serious.

PhD student Bruce Urch and Frances Silverman at University of Toronto’s Gage Occupational and Environmental Health Unit recently studied what happened to 33 healthy volunteers following controlled exposure to air pollution. Thirty-three of the subjects were Torontonians, who inhaled morning rush-hour emissions that had been collected right across from the U of T bookstore. At the same time, a colleague, Dr. R.D. Brook, studied 50 participants who breathed in air from Ann Arbor, Michigan.

Interestingly, the particulate matter in Toronto air caused more harm than the Ann Arbor sample. While both study groups showed increased blood pressure within minutes to hours, only the Toronto volunteers showed problems with their blood vessels, despite the fact that the concentrations of pollutants were nearly identical.

This suggests that the source of the pollution matters. The Toronto sample probably contained more car exhaust and less industrial pollution than the Ann Arbor sample, Urch says, and he is now doing further analysis.

It strikes me that, as a society, we are much more vigilant about food that’s bad than we are about poor air quality. If Toronto air was a hotdog, it would be pulled from the shelves. Instead, rather than requiring a single car to forgo its journey, we advise kids, the elderly and joggers to stay indoors, and try not to breathe too deeply. Maybe we should take those smog warnings a little more seriously.